Officials said the person with the gun was identified as a police officer who escorting a group of teens on an exchange program for a tour of the museum’s galleries. The officer, who was wearing a badge but was not in uniform, was carrying the gun in a holster.

The gun was never removed from the holster, university officials said.

The officer, who did not alert museum staff to his presence in advance, is cooperating with officers who responded to the incident, according to the post of Princeton’s website.

(AP Photo/Darron Cummings) In this Sept. 15, 2017 photo, U.S. Secretary of Education Betsy DeVos talks with Gracie Johnson during a hog roast before a high school football game between Eastern Hancock and Knightstown in Charlottesville, Ind.

The Trump administration is scrapping Obama-era guidance on investigating campus sexual assault, replacing it with new interim instructions for universities.

The Trump administration is scrapping Obama-era guidance on investigating campus sexual assault, replacing it with new interim instructions for universities.

(AP Photo/Evan Vucci) Rep. Richard Neal, D-Mass., left, and Rep. Kevin Brady, R-Texas, right, listen as President Donald Trump speaks during a meeting with members of the House Ways and Means committee in the Roosevelt Room of the White House, Tuesday, Se